WASHINGTON — Unlike most of the laws Congress passes each year, the massive health care bill President Obama will sign today is destined to affect nearly all American families.

Poor adults will get Medicaid. Low-income families will get federal subsidies to buy insurance. Small businesses will get tax credits. Children will be able to stay on parents' policies until they turn 26. Seniors will gain additional prescription drug coverage. People with medical conditions will gain peace of mind because insurers have to cover them.

On the other hand, the wealthy will pay higher taxes to help finance the 10-year, roughly $940 billion cost. Businesses with 50 or more workers will have to insure them or pay a penalty. Individuals, too, will have to pay a fine if they don't buy insurance. Premiums could rise for some people. Seniors with Medicare Advantage policies could lose those plans or pay more to keep them.

WASHINGTON — Senate Democrats vowed to start debate today on a series of changes to President Obama's landmark health care legislation, launching the final battle in the year-long effort to revamp the nation's health insurance system.

Work on the proposed "fix-it" bill, which eliminates special deals for individual states and increases subsidies to make insurance more affordable, will get underway after Obama signs into law the broader health care bill narrowly approved by the House of Representatives on Sunday.

House Democrats, including Speaker Nancy Pelosi of California, have cheered the 219-212 vote on Obama's health care proposal. But, like the health care bill itself, the follow-up package of changes has prompted a partisan feud in the Senate that could tie up the measure for days.